Spectrometers use light sources for the detection and quantification of emission or absorption of radiation by matter (e.g. individual molecules in analysis of gas or liquid phase compounds). The radiation from such light sources is absorbed or emitted with a particular energy determined by transitions occurring to the molecules of an analyte. For example, in infrared spectroscopy, discrete energy quanta are absorbed by molecules due to excitation of vibrational or rotational transitions of the intra-molecular bonds.
Variations in environmental conditions as well as aging can cause transmitted and/or detected power and/or beam shape of a light source within a spectrometer to change over time. A change in transmitted and/or detected power and beam shape in a spectrometer can alter the spectrometer calibration and cause spectrometer reading offsets. Such reading offsets can cause higher operating costs for a controlled process, costly replacement of equipment, including but not limited to catalytic converters, or harmful conditions to humans or the environment if harmful concentration limits of a measured analyte are being exceeded. In some cases, spectrometers suffering such issues require manual calibration or even replacement by a technician. Such service calls are costly and result in downtime for the spectrometer while such repairs are being performed.